Hargonet is a Class 15, making him the most powerful ghost ever. He first fought the Ghostbusters when he planned to create an army by opening their Containment Unit. The Ghostbusters fortunately recaptured all the ghosts and were able to trap Hargonet because he was weakening from using too much of his power, a la Ghostmaster. Later, he was freed and grew too powerful to recapture, so he was destroyed by being hit by four proton streams at full power and then crossing the streams. However, a Class 15 is so powerful, it can't even be destroyed. When he appeared again, the Ghostbusters defeated him by banishing him to another dimension.